Root Mean Square Calculator
Calculate the root mean square (RMS) of three numbers, used for AC voltages and error measures.
Formula: RMS = √((a² + b² + c²) / 3)
About Root Mean Square Calculator
Root Mean Square Calculator is a free online calculator that gives you an instant, accurate result as you type. Calculate the root mean square (RMS) of three numbers, used for AC voltages and error measures.
The calculation uses the standard formula RMS = √((a² + b² + c²) / 3) and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.
Household "230 V" or "120 V" mains ratings are RMS values — the peak AC voltage is √2 times higher.
Frequently Asked Questions
Is Root Mean Square Calculator free to use?
Yes. Root Mean Square Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.
How accurate is this calculator?
The calculator applies the standard formula (RMS = √((a² + b² + c²) / 3)) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.
Related Tools
30 60 90 Triangle Calculator
Find all sides and the area of a 30-60-90 special right triangle from its short leg.
45 45 90 Triangle Calculator
Find the hypotenuse and area of a 45-45-90 right isosceles triangle from its leg length.
Distance Formula Calculator
Calculate the straight-line distance between two points (x₁, y₁) and (x₂, y₂) on a coordinate plane.
Midpoint Calculator
Find the midpoint between two points (x₁, y₁) and (x₂, y₂) on a coordinate plane.
Slope Calculator
Calculate the slope of the line through two points, with the angle of incline in degrees.
Law of Cosines Calculator
Find the third side of any triangle from two sides and the angle between them using the law of cosines.